When constructing a norm for a language consisting of a variety of
dialects, a factor which has to be taken into consideration is the mutal
intelligibility of the dialects. Statements on this subject can, however, be
misleading as they may be subjective and subject to a certain ideology. Thus,
an objective linguist considers some North Frisian dialects to be so dissimilar
that mutal comprehension is practically impossible (Hofmann, 1956),
whereas certain eminent members of the language movement see no reason
why intra-dialectal comprehension should be difficult. It is, however,
difficult to find objective criteria for comprehensibility. Linguistic similarity
does not suffice, as socio-psychological factors such as prestige may render
two objectively similar languages incomprehensible. In Nigeria, speakers of
the Kalahari dialect of the I jo language are relatively prosperous and
consider the other dialect groups such as Nembe to be backward. The latter
have no difficulty in understanding Kalahari, whereas the Kalahari maintain
they are unable to understand the Nembe. This is an example of nonreciprocal
comprehension. Similarly, socio-political factors may be at work,
as exemplified in the Urhobo language in Southern Nigeria, where speakers
of the Isoko dialect group maintain they cannot understand the other
dialects of the language. This is accredited to the Isoko group's desire for .
autonomy (Heine, 1979).